Since the isolation of HCV, laboratory tests to detect anti-HCV antibodies in serum have been developed. Furthermore, in the absence of antigen tests, polymerase chain reaction has been used to demonstrate the presence of HCV RNA in the serum. In order to get a deeper insight into the virology events involved in hepatitis C, and to identify possible sites of extrahepatic replication which may serve as a source of reinfection, we are conducting a study to determine the distribution of both positive (genomic) and negative (replicative) stranded HCV RNA in patients with HCV infection, using serum and total peripheral blood mononuclear cells (PBMC).